1. Field of the Invention
The present invention relates to a card connector, and more particularly to a card connector in which a card insertion space is formed by a body made of an integral molded product of a synthetic resin, and a sheet metal frame attached to the body.
In some of the card connectors of this kind, a body comprises a head portion having multipolar contacts, and a pair of right and left arms which are extended from the head portion, so that the right and left arms guide insertion of a card. In such a card connector, when the right and left arms are deformed to be displaced outwardly or inwardly from their original design positions, the operability of card insertion is impaired, or a card cannot be sometimes inserted. In the case where both the right and left arms are deformed to be inwardly displaced, particularly, the slot width (the lateral dimension of a card insertion slot) is excessively small even when one of the arms is displaced at a small degree, thereby impairing the operability of card insertion. In an extreme case, a card cannot be inserted into the connector. In the case where a thin body which has a small width and a thickness of only about several mm (2 to 3 mm) is requested to be produced by integral molding of a synthetic resin, the above situation is particularly remarkable because, for example, increases of the thickness and width of the arms are limited.
The specification of Japanese Patent No. 2,533,829 (FIGS. 4, 9, and 14) (hereinafter, referred to as “Patent literature 1”) discloses a memory card connector. In the memory card connector, a reinforcement plate made of a sheet metal which cooperates with such a body to form a card insertion space is stretched between a pair of side guide arms (corresponding to the above-mentioned arms) of a connector housing made of a integral molded product of a synthetic resin. Retention tabs which are formed by bending right and left side edges of the reinforcement plate are inserted into slots (channels) which are formed in longitudinal middle portions of the side guide arms, respectively, thereby reinforcing the side guide arms. Patent literature 1 discloses also a structure in which a tang that is directly opposed to a grounding printed circuit for removing electrostatic charges from a main board is punched out in a tip end portion of the reinforcement plate, and a rectangular piece formed by a residual punching metal is inserted into a channel formed in the vicinity of the tip end of the corresponding side guide arm. In the memory card connector of Patent literature 1, recessed edges formed in a lower plate portion which is continuously integrated with the pair of side guide arms and a head portion have a rectangular shape.
The specification of Japanese Utility Model Registration No. 3,086,612 (hereinafter, referred to as “Patent literature 2”) discloses an electronic card connector in which a reinforcement plate is extended between longitudinal middle portions of right and left side arms, the right and left side arms and the reinforcement plate are integrally molded by a synthetic resin, and the profile of the tip end edge of the reinforcement plate is formed into a recessed shape.
In the connector disclosed in Patent literature 1, the right and left retention tabs of the reinforcement plate are simply inserted into the slots configured by channels formed in the respective longitudinal middle portions of the pair of side guide arms. Although each of the side guide arms can be prevented from being deformed in a range between the inserted portion and the basal portion of the side guide arm, therefore, a portion which is closer to the tip end than the inserted portion serving as a portion for forming a card insertion slot cannot be effectively prevented from being deformed. In the case where the thickness and width of the side guide arms are reduced so as to thin and narrow the connector housing, the card insertion slot is excessively narrowed by deformations, particularly, inward deformations of the side guide arms, and the possibility that the operability of card insertion is impaired is increased. In order to form the slots into which the retention tabs of the reinforcement plate are to be inserted, the reduction of the widths of the side guide arms is limited. In the case where the connector housing is requested to be further narrowed and thinned, therefore, even the slots into which the retention tabs are to be inserted cannot be formed in the side guide arms. Consequently, the technique disclosed in Patent literature 1 in which the side guide arms are reinforced by inserting the retention tabs of the reinforcement plate into the slots formed in the side guide arms has a difficulty in promoting narrowing and thinning of the connector housing. Patent literature 1 discloses also the structure in which the rectangular piece in the tip end portion of the reinforcement plate is inserted into the channel formed in the vicinity of the tip end of the corresponding side guide arm. Although the structure can prevent each of the side guide arms from being deformed in a range between a vicinity of the tip end of the side guide arm and the inserted portion, the foremost end portion of the side guide arm cannot be prevented from being deformed. Since the channel for inserting the rectangular piece must be formed in the side guide arm, moreover, the above-discussed difficulty in promoting narrowing and thinning of the connector housing cannot be solved.
By contrast, Patent literature 2 simply discloses the technique in which, in the case where the reinforcement plate and the right and left side arms are integrally molded by a synthetic resin, even when the reinforcement plate is warped and the lateral middle portion of the card insertion slot is narrowed, a card inserted into the card insertion slot gradually pushes the lateral middle portion of the reinforcement plate, and the card is enabled to be inserted. The technique cannot solve the problem in that the right and left side arms are inwardly deformed to excessively narrow the card insertion slot.
As described above, Patent literature 1 discloses only the technique in which the right and left side guide arms are reinforced by using the reinforcement plate, and the reinforcement plate disclosed in Patent literature 2 simply provides the technique of reinforcing the right and left side arms. These literatures fail to provide a technique in which right and left arms are prevented from being deformed in an ensured manner based on the design, thereby improving the operability of card insertion and enabling a card connector to be easily narrowed and thinned.
The invention was developed in view of the above-mentioned circumstances. It has been found that a phenomenon in which right and left arms are deformed to be inwardly displaced from their original design positions because of a problem of the molding technique does not occur in the case where a body is provided with a lower plate portion which is extended between the right and left arms, a recessed portion that is recessed toward such a head portion is formed in the lower plate portion, and right and left recessed edges of the recessed portion are formed into an arcuate shape to enhance the breakage resistance. It is an object of the invention to provide a card connector in which a structure for preventing a pair of right and left arms from being deformed without forming a slot in the arms as disclosed in Patent literature 1 and properly positioning the arms to their original design positions is produced, so that, even when the card connector is further narrowed and thinned, the lateral width of a card insertion slot which is formed between the foremost ends of the right and left arms is adequately defined and the operability of card insertion is maintained to a satisfactory level.
It is another object of the invention to provide a card connector in which right and left arms are prevented from being inwardly deflected, whereby card insertion can be prevented from being impaired in operability or disabled.
It is a further object of the invention to provide a card connector in which a sheet metal frame that cooperates with a body having arms to form a card insertion space is used so as to eliminate causes of impairing the operability of card insertion by deforming the arms, without increasing the number of parts.
It is a still further object of the invention to provide a card connector of excellent durability in which, even when the card connector is narrowed and thinned by reducing the thickness and width of each of right and left arms, the arms can be provided with sufficient strength without increasing the number of parts.